related pages

Steel frame

Using steel frame for the whole of a house structure is very uncommon in the UK. Usually the clear spans required for a house can be achieved using timber with the incorporation of occasional steel members such as RSJsrolled steel joists where masonry spans a window or door. There are published tables of timber spans for standard roof joists, floor joists etc. which comply with the Building RegulationsThese are the mass of regulations that cover safety, health, welfare, convenience, energy efficiency etc. in the way buildings are constructed. Not to be confused with Planning consent (which is more to do with whether you can put up the building in the first place). See more on the regulations. (See Structural Timber) It can be very difficult to prevent cold bridgingthis is a pathway where heat can easily escape (or get in) through some part of the structure. It is usually caused by some element of structure such as a steel lintel or wooden studwork. Also known as a thermal bridge. see more on
cold bridging where steel members are incorporated into the external structure especially where PassivhausSee more on the Passivhaus standard. The PassivHaus Institute has pioneered a standard for low energy buildings. It includes very low energy usage and ways of achieving this. The word is derived from the idea of buildings which are fundamentally low energy and passive solar heated rather than using extra gadgets to heat them. See Passivhaus for the UK branch of the organisation. or zero carbonbit of a slippery fish. It tends to mean that a building uses no carbon (oil, coal, etc) to heat it (meaning in a 'net' way). It usually ignores the carbon which goes into building it (the embodied energy). See the page on Zero Carbon? standards are to be met

It is becoming increasingly popular to incorporate elements of steel framework into timber frame and kit houses (see RSJs in the center of the picture) in order to achieve larger spans than are normally available with timber. This is often down to the preferences of the engineer doing the calculations rather than being an inherent necessity. Very often laminated timber would do the job better in several ways

lower embodied energythe total amount of energy it takes to make a material (or a building). See more on embodied energy

less thermal conductivity. As the insulation standards for housing become more stringent, cold bridging becomes more of a problem and steel is a particularly poor insulator. This may be important in outside walls or at the bottom and top of columns. With Passivhaus or code 6 standards it may be necessary to position the steel elements on the inside of the main envelope to avoid thermal bridgingthis is a pathway where heat can easily escape (or get in) through some part of the structure. It is usually caused by some element of structure such as a steel lintel or wooden studwork. Also known as a cold bridge. see more on
thermal bridging.

better fire performance (steel usually needs cladding to protect it from fire whereas timber is usually simply increased in width by 25mm per exposed face to give fire protection.)

steel erector not required (though for small jobs a general contractor can usually handle the erection work)

It’s easier to adapt or modify timber beams and it’s easier to fasten to them.

timber columns can usually go straight onto the foundation slab whereas steel requires fixing plates set in the concrete. The point here is that timber columns can be made slightly over length and trimmed on site whereas steel columns usually need nuts and studs or bolts with shims to make final adjustments. See the section on the Segalrefers to a simple self build timber frame form of construction pioneered by the architect Walter Segal. see details of the system method.